Avid Pokémon GO players may have noticed something missing from the immensely-popular mobile game earlier today, November 5. It turns out that weather effects were temporarily removed due to a temporary issue, but you can rest assured that Niantic has since dispatched a fix. The official announcement from the developemnt team is as follows:
There was a brief interruption from our weather provider, which caused weather to temporarily be removed from Pokémon GO. It should be restored within a few hours.
Source: Niantic Support @NianticHelp